"Then there isn't any salt mine down there," went on Roger in a disappointed tone, his interest in that matter overshadowing, for a moment, his joy at having helped save the men. "Nary a bit of a salt mine," said Tom. "But I'll back the salt lake down there, against most anything outside of Utah. Hey, Jim?" "That's right," assented his companion, wiping the salt water from his eyes. "How did it happen?" asked Adrian. "Now you're talkin'," said Tom. "We were diggin' away, or rather I was, and Jim was up above. I'd got about as deep as where Mr. Vanter said we ought to strike rock salt, and I was givin' some hearty blows with my pick, when, all on a sudden, the pick goes through with a pop, jest like when you stick a pin in one of them red balloons you buy at the circus. First thing I knew I was up to my neck in water saltier 'n' any ever tasted. Wow! But I didn't know what I'd struck, the Atlantic Ocean or the Dead Sea." "I guess it was a little of both," interposed Jim. "Right you are, Jim. Well, as it happened I landed right on a ledge of rock, or I might have gone on clean through to China," resumed Tom. "As soon as I got my wind I sung out to Jim. All the while I was holdin' on to a projectin' stone in the side of the shaft. When I yelled to Jim I wanted him to lower the rope to me. But he got excited, or something and, after he had unwound it, and lowered it, he shinned down it himself, hand over hand. Then before he could stop himself he was in the water with me, both of us as wet as drowned rats, at the bottom of a shaft thirty feet deep. We could just make out to find room on the narrow ledge, or we'd both been in the bottomless pit. We tried to climb up the rope, but, not bein' sailors or circus fellows, we didn't make out worth a cent. So we both began to yell as hard as we could, and--well, you know the rest. My! Oh! But it's glad we are that you boys came along when you did, or we'd both be fairly pickled away in brine for the winter. How about it, Jim?" "That's what," said Jim, heartily, wringing about a quart of salt water from his coat. "But I can't understand how the brine got down there," said Roger. "Mr. Vanter expected to strike rock salt, and the white crystals I brought up were certainly solid enough. I can't see why there should be salt water, unless there's a spring of fresh water that has become brine from dissolving the rock salt. I must hurry to tell Mr. Vanter."